Counterpoising and equipoising mechanism



Aug. 30, 1966 w. P. IGGULDEN COUNTERPOISING AND EQUIPOISING MECHANISMFiled Oct. 19, 1964 arllff"!lilllll'l'fllllllllIIil'lll'l'llII'I'I'iIlIII Q INVENTOR wiLuAM P-IGGULDEN United States Patent 3,269,684 COUNTERPOISING AND EQUIPOISINGMECHANISM William Palmer Iggulden, 713717 Nepean Highway East Brighton,Victoria, Australia Filed Oct. 19, 1964, Ser. No. 404,606 6 Claims. (Cl.248280) This invention relates to counterpoising or equipoisingmechanism such as is used for supporting lamps, hair dryers,microphones, optical apparatus and other articles, the article beingsupported by a structure consisting of one or more pivoted arms and theweight of the whole being counterpoised or equipoised by one or morecounterbalancing springs.

In such mechanisms the counterbalancing springs have hitherto beenconnected directly to the supporting structure. In some cases, thesprings have been enclosed within the pivoted arms of the structurebetween attachment points. Such general constructions, although oftenefficient, have the disadvantage that the length of the spring isgoverned by the distance between the attachment points, or conversely,the spacing of the attachment points is governed by the springrequirements. Access to the springs for adjustment or other purposesalso can be difficult.

The object of the present invention is to overcome these disadvantages.

According to the invention, there is provided counterpoising orequipoising mechanism comprising a main supporting member, :a firstsupporting Iarm pivoted by a pivot pin to said main supporting member, asecond supporting arm pivoted to a pin which is supported pivotally fromthe pivot pin of the first supporting arm by means of short links andtwo counter-balancing coiled springs arranged beyond or away from thearms and each secured near one end to the main supporting member, onespring having its other end connected through an interposed member tothe first supporting arm and the other spring having its other endconnected through an interposed member to the pin on which the secondsupporting arm is pivoted.

The invention is more fully described aided by reference to theaccompanying drawings illustrating the preferred embodiment of theinvention as applied to a lamp. In these views:

FIG. 1 is a side View of the complete lamp and mechanism.

FIG. 2 is a plan view of portion of the mechanism showing the connectionof the springs.

FIG. 3 is a section on line 33 of FIG. 2.

FIG. 4 is a section on line 4-4 of FIG. 3.

FIG. 5 is a sectional view of one of the spring units.

FIG. 6 is a detail sectional view illustrating the mounting of thespring units.

As is shown in these views, the mechanism comprises a bracket 2 having aplate 3 adapted for suitable attachment to a wall, ceiling or otherconvenient surface as by means of screws 4 or the like. The outer end ofthe bracket has a tubular member 5 swivelly supporting a main supportingmember 6.

The lower end of the member 6 is bifurcated and pivotally supports bymeans of a pin 7 one arm 8 of a twin arm arrangement. The other arm 9 ofsaid arrangement is pivoted to a pin 10 which is pivotally supportedfrom the pin 7 by means of short links 11. The arm 8 is preferably ofchannel-shape in cross-section while the arm 9 is of box-like sectionand is of lesser width than the other arm 8 so that it telescopes withinsaid arm as shown in FIG. 4 as the arms are pivotally moved.

The outer ends of the two arms 8 and 9 are pivotally connected as at 12and 13 to an extension arm 14 which at its outer end supports thearticle to be supported. The drawings show a shaded lamp as 15 withswitch 16. Preferably, the lamp or other article is connected to theouter end of the extension arm 14 by means of a pivotal fitting 17 and aswivel fitting 18 so that the position of the lamp or article isuniversally adjustable.

The main supporting member 6 supports two tubular casings 19 and 20 eachenclosing a coiled counter-balancing spring 21. The springs are seatedat one end against a closed bottom 22 on each casing and encircle rods23 and 24 respectively which slidably extend out of the casings throughholes 25 in the bottoms 22. The other ends of the springs are seatedupon plungers 26 attached to the inner ends of the rods 23 and 24respectively and slidable in the casings 19 and 20. Thus, the coiledsprings exert pressure on the plungers 26 as the rods 23 and 24 aremoved. The upper ends of the casings 19 and 20 may be closed by means ofinserted plugs 27.

The rod 23 from the casing 19 is connected to a pin 28 on the arm 8close to its pivot pin 7 while the rod 24 from the other casing 20 isconnected to the pivot pin 10 of the other arm 9.

The operation of the mechanism will be obvious. As the arms 8, 9 and 14are articulated in obtaining the required adjusted position of the lamp15, or other article, the rods 23 and 24 and plungers 26 are moved inthe casings 19 and 20 and apply pressure to the coiled springs 21 insuch manner as to counterbalance the weight of the supported partsincluding the lamp 15 or other supported article and the arms 8, 9 and14.

To enable the casings 19 and 20 to automatically adjust their positionsto suit the angular positions of the rods 23 and 24, said casings arepreferably pivotally mounted on a pin 29 on the main supporting member6. To facilitate assembly, the pin 29 may have heads 30 on its endswhich are engaged by slotted fittings 31 secured to the casings 19 and20.

It will be obvious from the above that the coiled counterbalancingsprings 21 are disposed beyond or away from the two points 10 and 28 ofthe equipoise structure to which the spring force is applied, the springforce being applied, in the case of one spring through theintermediat-ory plunger 26, the rod 23 and the pin 28 to the arm 8 and,in the case of the other spring, through the intermedia-tory of theplunger 26, the rod 24 and the pin 10.

Some of the advantages obtained with the improved mechanism, asdescribed, are improved balancing properties, particularly in the caseof special applications, more convenient adjustment of the springsbecause of their greater accessibility in the casings 19 and 20 and alsoa generally improved appearance of the mechanism.

To lock the mechanism in an adjusted position, the pin 7 may bescrewthreaded at one end and fitted with a clamping finger nut 32 which,in effect, tightens the pivotal joint at the pin 7. The bracket 2 mayalso be of hollow two-piece construction to house a junction fitting forthe electric power supply leads 33. From said fitting leads are passedthrough the tubular member 5 of the bracket, the main supporting member6, the arm 9 and the extension arm 14, which is also tubular, to theswitch 16 and the lamp 15 or other supported article.

What I claim is:

1. Counterpoising or equipoising mechanism comprising a main supportingmember, a first supporting arm of channel shape pivoted at one end by afirst pivot pin to one end of said main supporting member to swing inthe same plane, a second supporting arm of lesser width and telescopinglongitudinally in the channel of the first arm, said second arm beingpivoted to swing in said plane and slightly away from the first arm by asecond pin which is supported pivotally from said first pivot pin by ashort link, a single pair only of counterbalancing coiled springs eachenclosed in a tubular casing and disposed one on either side of saidmain supporting member, means securing said casings directly to andbeside the main supporting member, one end of each spring being seatedon a closed bottom of its casing, the other end of each spring beingseated on a plunger adjustable along the inner end of a rod whichslideably extends out of the casing through an aperture in said bottom,the outer end of one of said rods being pivoted to a third pivot spacedfrom said first pivot on the first supporting arm, and the other end ofthe other rod being pivoted to said second pin.

2. Counterpoising or equipoising mechanism according to claim 1 whereinsaid means securing each said casing comprises a pin extending outwardlyfrom the main support and having an outer head, a fitting secured toeach casing having a longitudinal slot therein opening toward the bottomof the casing to slideably and pivotably receive the head of said pin onthe main support.

3. Counterpoising or equipoising mechanism as claimed in claim 2 whereinthe outer ends of the two supporting arms are pivotally connected to anextension arm which, at its outer end, supports an article to besupported by means of a pivotal fitting and a swivel fitting.

4. Counterpoising or equipoising mechanism as claimed in claim 2 whereinthe main supporting member is swivelly supported from a bracket adaptedfor attachment to a wall, ceiling or other surface.

5. Counterpoising or equipoising mechanism as claimed in claim 4 whereinthe bracket is of hollow two-piece construction to house a junctionfitting for electric power supply leads and leads from said fittingextend through the bracket, the main supporting member and the arms tothe supported article.

6. Counterpoising or equipoisin-g mechanism comprising a main supportingmember, a first supporting arm pivoted at one end by a first pivot pinto one end of said main supporting member to swing in the same plane, asecond supporting arm movable longitudinally of the first arm, saidsecond arm being pivoted to swing in said plane and slightly away fromthe first arm by a second pin which is supported pivotally from saidfirst pivot pin by a short link, a single pair only of counterbalancingcoiled springs disposed one on either side of said mainsupportingvmember, means securing one end of each said springs directlyto and beside the main supporting member, the other end of each springbeing secured to a collar adjustable along a rod, the end of one of saidrods being pivoted to a third pivot spaced from said first pivot on'thefirst supporting arm, and the end of the other rod being pivoted to saidsecond pin.

References Cited by the Examiner UNITED STATES PATENTS 2,036,097 3/ 1936Pieper 248--280 X 2,700,524 l/l955 Lauterbach 248-280 FOREIGN PATENTS237,596 2/ 1962 Australia. 189,254 5/ 1937 Switzerland.

CLAUDE A. LE ROY, Primary Examiner.

R. P. SEITTER, Assistant Examiner.

1. COUNNTERPOISING OR EQUIPOSING MECHANISM COMPRISING A MAIN SUPPORTINGMEMBER, A FIRST SUPPORTING ARM OF CHANNEL SHAPE PIVOTED AT ONE END BY AFIRST PIVOT PIN TO ONE END OF SAID MAIN SUPPORTING MEMBER TO SWING INTHE SAME PLANE, A SECOND SUPPORTING ARM OF LESSER WIDTH AND TELESCOPINGLONGITUDINALLY IN THE CHANNEL OF THE FIRST ARM, SAID SECOND ARM BEINGPIVOTED TO SWING IN SAID PLANE AND SLIGHTLY AWAY FROM THE FIRST ARM BY ASECOND PIN WHICH IS SUPPORTED PIVOTALLY FROM SAID FIRST PIVOT PIN BY ASHORT LINK A SINGLE PAIR OF COUNTERBALANCING COILED SPRINGS EACHENCLOSED IN A TUBULAR CASING AND DISPOSED ONE ON EITHER SIDE OF SAIDMAIN SUPPORTING MEMBER, MEANS SESURING SAID CASING DIRECTLY TO ANDBESIDE THE MAIN SUPPORTING MEMBER, ONE END OF EACH SPRING BEING SEATEDON A CLOSED BOTTOM OF ITS CASING, THE OTHER END OF EACH SPRING BEINGSEATED ON A PLUNGER ADJUSTABLE ALONG THE INNER END OF A ROD WHICHSLIDEABLY EXTENDS OUT OF THE CASING THROUGH AN APERTURE IN SAID BOTTOM,THE OUTER END OF ONE OF SAID RODS BEING PIVOTED TO A THIRD PIVOT SPACEDFROM SAID FIRST PIVOT ON THE FIRST SUPPORTING ARM, AND THE OTHER END OFTHE OTHER ROD BEING PIVOTED TO SAID SECOND PIN.